Apparatus for the control of gun-fire.



A. BARR & W. STROUD.

APPARATUS FOR THE CONTROL OF GUN FIRE.

APPLICATION FILED NOV,14. 1914.

1,187,234. Patented June 13, 1916.

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ARGI-IIBALD BAR-R AND WILLIAM STROUD, OF ANNIES-LAIND, GLASGOW, SCOTLAND.

APPARATUS FOR THE CONTROL OF GUN-FIRE.

Specification of Letters Patent.

Patented June 13, 1916.

Application filed November 14, 1914. Serial No. 872,184.

To all whom it may concern:

Be it known that we, ARCHIBALD BARR and WILLIAM S'rnoUD, subjects of the King of Great Britain and Ireland, and both of Caxton street, Anniesland, Glasgow, Scotland, have invented new and useful Improvements in Apparatus for the Control of Gun-Fire, of which the following is a specification.

Our invention has reference to a device for estimating the probable value of the range from a number of observations of range (not necessarily absolutely concordant) such as may be furnished by a rangetaker observing upon a target at frequent intervals of time, and, if required, the value of the rate of change of range. For this purpose we transmit the indications of the rangefinder to a station where the observations may be collated, either mechanically when, for example, the whole apparatus is situated in a turret, or electrically when the observations are transmitted, say to the fire control station where the subsequent operations are carried out.

The transmission of the indications of the range finder may either take the form of transmitting (1) by equal steps of movement of the working head of the instrument or (2) by equal increments of range.

According to this invention we provide a movable indicator, which is displaced from a reference position in accordance with changes of range, as observed by the rangetaker (each observation not being necessarily an accurate measurement of the range of the target) and adapted to be returned, by operation of mechanism independent of the rangefinder, to the reference position, and, in association therewith, means by which the average of a series of observations may be estimated.

We shall at first assume that we transmit by equal steps of movement of the working head and we shall further assume that the transmission is electrical.

At the fire control station we provide a receiver which is moved forward or backward in accordance with the motion of the working head. This receiver moves a piece carrying an indicator which may, for example, consist of a pen or pencil moved across the surface of a sheet of paper moving in a direction perpendicular to the direction of motion of the pencil. We may also provide means for causing the pencil to strike the paper and leave a mark thereon recording 1ts position at any moment, to be actuated when desired by the rangetaker after a good observation has been taken. By these means a record of the positions of the working head, at successive times, upon a sheet of moving paper could thus be obtained. It will be clear that if we were transmitting and recording 2000 positions of the working head and if each step was arranged to produce a readily visible motion of the pencil, say the paper would require to he, say, 200 broad. This condition however is obviated by our invention which provides that the required indications shall be made in the region of one and one only reference position and this enables the records to be made on a moving sheet of paper of comparatively narrow width. This we may conveniently accomplish by Wiping out, or annulling, the motion of the pencil by imparting an equal .or nearly equal amount of opposite motion to it. One method of accomplishing this result is to arrange that the receiver operates one element 1 of a differential gear 1 2 3, the jockey element 2 of which operates the pencil, while the element 3 is operated by a mechanism we shall call a converter which may take the form of a toothed drum and pinion as described in specification of British Patent No. 29870 of 1912, and forming the subject matter of United States application for patent, filed 12th December, 1913, Serial No. 806262, in which a series of teeth arranged in appropriate positions drive the pinion intermittently. This pinion is geared to the element 8 of the difierential gear.

The teeth on the drum may be so arranged that every revolution corresponds to a change of range of definite amount, say yards, and then the number of teeth operating during that revolution will be arranged to be such that the amount of motion communicated by the pinion to the element 3 shall be equal and opposite to the amount of motion communicated to the element 1 by the receiver for that particular interval of 100 yards. These respective amounts of motion per 100 yards will almost invariably be very much less at high ranges than at low, but the amount of motion will depend upon the nature of the operating gear of the rangefinder.

In one method of dealing with conditions appertaining to a changing range the aforesaid toothed drum may be driven forward or backward at a definite but variable rate by any suitable means, such, for example, as a friction disk capable of being moved diametrically across the surface of a uniformly rotating friction wheel.

In order to utilize the record of the observations of the position of the working head to get the range and rate of change of range we may proceed as follows: Along the middle of the moving sheet of paper and parallel to the direction of motion we may provide as the reference position a fixed line or a line upon the paper. \Ve now turn the toothed drum either by means of a separate handle working through an additional differential gear or by moving the friction disk until the positions of the pencil marks fall near the line, and we then proceed to carefully adjust the position of :(1) the toothed drum until the line falls midway between the pencil marks, and, (2) the friction disk so that the line keeps midway between the marks.

An indicator consisting, for example, of a pointer moving on a dial (or a set of indicating drums) may be actuated by the toothed drum and used to show the value of the range at any time, and the position of the friction disk upon the friction wheel gives the value of the rate of change of range.

In cases where a converter is situated at the rangefinder and the transmission is by equal intervals of range, the aforesaid toothed drum will not be required at the fire control station, and the element 1 of the differential gear may be operated directly by the receiver and the element 3 be geared directly to the friction disk. It will be seen that in this latter case the motion of the pencil is proportional to the change of range, whereas in the previous case it was proportional to the change in position of the working head of the rangefinder.

Any other form of apparatus may be used instead of the aforesaid drum provided it will accomplish the purpose of converting from one type of scale into another.

An example of construction embodying the principal features of this invention will now be described with reference to the ac companying drawing which shows an apparatus adapted for use in making observations on a target at a constant or varying range.

In the drawing the motions of the working head of the rangefinder are communicated to a bevel wheel (1) either mechanically or electrically by means of any suitable type of receiver with or without a relay. The bearing of the jockey element 2 of a differential gear 1 2 8 is fixed to a shaft 4 carrying a drum 5 on the surface of Which there is a long spiral groove of open pitch in the middle as shown in the figure. In the groove of this spiral there engages a pin 6 fixed to a frame 7 feathered upon a rod 9 and carrying the indicator which may consist of a pen or pencil 8. In this Way it will be seen that if the element 3 of the differential gear remains stationary, every movement of the working head of the rangennder is communicated to the grooved drum 5 and is accompanied by a lateral motion of the pencil 8. After a good observation has been obtained by the rangetaker, the pencil 8 is momentarily depressed to make a mark upon a strip of paper 10 which is being moved upward by suitable mechanism, the pencil 8 at other times being out of contact with the paper. A central line 11 constituting the position of reference may be marked upon the paper, or otherwise fixed laterally in relation to the paper.

Suppose now we start with the pencil S in the central position and that the working head of the range finder is gradually moved indicating (say) higher and higher ranges, then the frame 7 will gradually be moved communicating motion to the marker (say) to the right, away from the position of reference, and finally the pencil marks would no longer fall upon the paper. In order to return the pencil 8 to the region of the line 11, we provide means for wiping out or annulling the effect of the motion of the working head upon the pencil S by imparting suitable motions to the element 3 of the differential gear. These operations may be carried out in the following way :12 is a friction disk rotated at a constant rate by suitable mechanism. Upon this disk there rolls a friction wheel 13 feathered upon a shaft 14. This friction wheel may be moved diametrically across the face of the disk and set in any desired position by the mechanism shown, consisting of two quick pitched screws 18 and 19, carrying the two nuts 15 and 16 respectively, attached to a piece 17, which embraces the friction wheel 13. These two screws may be simultaneously and equally rotated, say, by moving a bevel wheel 20 by hand, which causes the rotation of a bevel 21, spur wheel 22 fixed to 21, and thereby spur wheels 23 and 24: fixed on the screws 18 and 19 respectively. Thus by moving the bevel wheel 20 we can arrange that the friction wheel 13 shall rotate forward or backward at any rate below a cer tain maximum.

The shaft 14 has attached to it the bevel 31 of a differential gear 31, 82, 33, the object of which will be presently explained. e shall suppose now that the bevel 33 is stationary and that the bearing of the jockey 32 is fixed on the shaft of a bevel 35 gearing into a bevel 36, which turns an intermittently toothed drum 37, the drum 37 and bevel 36 being both fixed on the same axial shaft. This toothed drum is constructed upon the lines described in the specification of British Patent No. 29870 of 1912, and forming the subject matter of United States application for patent, filed 12th December, 1913, Serial No. 806262, and has about its surface a helical race provided with teeth 38, 38, spaced unequally apart of which only a. few are shown in the figure. As the toothed drum 37 is turned a screw 39 is suitably rotated by spur wheels 40 and 41 fixed to the drum and screw respectively. Upon screw 39 is a nut 42 guiding a carryover wheel 43 feathered upon a shaft 44. The pitch of the screw 39 and the relationship of the spur wheels 40 and 41 is such that the nut 42 and consequently the carryover wheel 43 is so moved along parallel to the axis of the drum 37 that the wheel 43 progressively follows the helical race upon drum 37. The wheel 43 has only a few teeth so placed with reference to the teeth on the drum that whenever one of the teeth 38 of the helical race passes under 43, the latter is rotated through a fraction of a whole turn, the fraction depending upon the number of teeth upon 43. e thus get an intermittent motion of the shaft 44 whenever a tooth of the drum 37 passes under 43 and this motion is communicated to the bevel 3, say, by spur wheels 45 and 46 fixed to the shaft 44 and the bevel 3 respectively.

The object of the differential gear 31, 32, 33, is to facilitate the original (or any necessary subsequent) setting of the toothed drum 37 so as to bring the pencil 8 opposite the line 11. For this purpose we may provide mechanism for rotating the element 33 of the differential gear, say, by fixing 33 to a bevel 34 operated by a bevel 47 which may be turned by hand.

It will be clear that when the rangetaker is making observations the range of the target can be indicated at any moment from the position of the toothed drum 37 or from the position of the nut 42 upon the screw 39. It may, for example, be exhibited by a series of carryover drums 48 of well-known type, operated by the rotation of the drum 37.

e shall first of all consider the method of using the apparatus for averaging the results of a series of measurements for a range which is constant. In this case the rate of change of range being zero, the frietion wheel 13 must be placed at the center of the friction disk 12, and the wheel 47 must be manipulated so as to bring the pencil near the line of reference 11. As the paper 10 moves upward marks are recorded upon it whenever a good observation has been obtained by the rangetaker, and it will be clear that if these marks are all to one side of the line of reference, the range'as indicated by the indicating drums 48 is too high, or too low as the case may be. The operator must now delicately set the wheel 47 until the subsequently produced pencil marks lie on the average as much to the right as to the left of the line of reference, when the correct range will be given by the drums 48.

In the case of a moving target the operator adjusts the wheel 47 as before, but now as the range alters the pencil marks will gradually shift to the right or left of 11, and it will be necessary to adjust the friction wheel 13 relatively to the friction disk 12, so that the toothed drum 37 is rotated at a suitable rate. It will be clear, however, that when, after adjustment of the rate of change wheel 20, we have satisfied the condition that the line of reference 11 lies evenly between the pencil marks, then the range at any moment can be read off from the indicating drums 4S and the rate of change of range can be read off from the position of the friction wheel 13. or from the position of the wheel 20, relatively to a fixed pointer, and this information can then be forwarded to the guns and there utilized for gun-setting.

It will be clear that we may, if desired, adapt the apparatus for recording the motions of the working head of two (or more) rangefinders. In this case it will be neces sary to duplicate (or triplicate, etc.) the differential 1, 2, 3, grooved drum 5 and parts 6, 7, S and 9, the two pens 8 and 8 (say) might then be arranged the one just over and beyond the other, and so that their lateral motion would not interfere with one another. It may be convenient in such an arrangement that ink of two or more distinct colors should be employed one for each pen so that the records of the two (or more) rangefinders may be discrimi nated. If desired, one (or more) of these records may be ignored.

Instead of the type of toothed drum 37 with teeth 38, we may use any other known means for converting from one type of scale into another. such as c. 0. that described in the specification of our British Patent No. 11772 of 1911.

1. Apparatus for the control of gun fire comprising a movable indicator, mechanism by the operation of which the indicator may be moved away from and returned to a reference position, range transmission means for transmitting motion in aecordance with changes of range for so operating the mechanism, that it acts to move the indicator away from the reference position, and annulling transmission means for so operating the mechanism that it acts to return the indicator to the reference position, the range and annulling transmission neously, and means by which the average of a series of positions occupied at different times by the indicator relatively to the reference position may be estimated, for the purposes set forth.

2. Apparatus for the control of gun fire comprising a movable indicator, mechanism by the operation of which the indicator may be moved away from and returned to a reference position, range transmission means for transmitting motion in accordance with changes of range for so operating the mechanism that it acts to move the indicator away from the reference position, and annulling transmission means for so operating the mechanism that it acts to return the in dicator to the reference position, the range and annulling transmission means being adapted to operate simultaneously, a traveling surface moving in a direction perpendicular to the direction of motion of the indicator, a marker carried by the indicator for producing at any moment a record on the traveling surface of the position of the indicator at the time of marking relative to the reference position, for the purposes set forth.

3. Apparatus for the control of gun fire comprising a traveling surface moving in one direction, an indicator movable in a direction perpendicular to the direction of motion of the traveling surface, a line parallel to the direction of motion of the traveling surface constituting a reference position, mechanism by the operation of which the indicator may be moved away from and returned to the reference position, range transmission means for communicating motion in accordance with changes of indications of range for so operating the mechanism that it acts to move the indicator away from the reference position, and annulling transmission means for communicating motion and so operating the mechanism that it acts to return the indicator to the reference position, the range and annulling transmission means being adapted to operate simultaneously, a marker carried by the indicator for producing at any moment a record on the traveling surface of the position of the indicator at the time of marking relative to the reference position, for the purposes set forth.

el. Apparatus for the control of gun fire comprising a movable indicator, mechanism by the operation of which the indicator may be moved away from and returned to a reference position, differential gear, one element (the driven) of which is in driving connection with the mechanism, range transmission means for transmitting motion in accordance with changes of range to a second element of the differential gear, and annulling transmission means for transmitting motion to a third (the complementary) element of the differential gear, the range and annulling transmission means being adapted to operate simultaneously, and means by which the average of a series of positions occupied at different times by the indicator relatively to the reference position may be estimated, for the purposes set forth.

5. Apparatus for the control of gun fire comprising a movable indicator, mechanism by the operation of which the indicator may be moved away from and returned to a ref erence position, range transmission means for transmitting motion in accordance with the movements of the working head of a range finder for so operating the mechanism that it acts to move the indicator away from the reference position, and annulling transmission means, for so operating the mechanism that it acts to return the indicator to the reference position, the annulling transmission means comprising a converter for transforming the motion transmitted from motion applied according to a uniform scale into motion communicated according to a variable scale corresponding to movements of the working head indicating equal increments of range, the range and annulling transmission means being adapted to operate simultaneously, for the purposes set forth.

6. Apparatus for the control of gun fire comprising a movable indicator, mechanism by the operation of which the indicator may be moved away from and returned to a reference position, range transmission means for transmitting motion in accordance with changes of range for so operating the mech anism that it acts to move the indicator a ay from the reference position, and annulling transmission means for so operating the mechanism that it acts to return the indicator to the reference position, a constant rate driving mechanism, means for obtaining from the driving mechanism a drive at variable speeds and means for applying the drive to the annulling transmission means, the range and annulling transmission means being adapted to operate simultaneously, for the purposes set forth.

AROHIBALD BARR. WILLIAM STROUD.

lVitnesses ARLINE DAVIES, OSWIN EDWIN HO\VARD BIROHALL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

